Based on the former, Louis van Gaal is likely to use the current month to strengthen his side at the back ahead of the second half of the season.

While the club's central defensive options remain the key cause for concern, the Dutchman will undoubtedly look to upgrade his current full-backs, should the opportunity arise.

United's only natural right-sided defender, Rafael da Silva, was named as one of several players told they could leave the club in the summer - a risky move considering United had no real back-up.

The Brazilian's susceptibility to injury, as well as his tendency to produce moments of madness, suggests to even the most casual of football fans that van Gaal will at some stage seek a replacement, with the January transfer window posing the perfect chance to do so.

Below we take a look at three realistic wing-backs who could make the move to Old Trafford in the near future.

Lukasz Piszczek has been a quietly excellent performer at Borussia Dortmund for many seasons now. Admired for his speed and quality of distribution, he is a cornerstone of Jurgen Klopp's Dortmund side that have experienced so much success in recent years.

The Polish international is widely regarded as one of the most accomplished right-backs in the modern game, and rightly so. This season he has made 16 appearances, while winning 64% of his attempted tackles, 68% of his headed duels and 53% of his take-ons, while operating down the flank.

Having won Bundesliga titles, challenged for domestic cups and featured in a Champions League final for the German outfit, one would argue he has little more to achieve with the club. At 29 years of age, now is the perfect time in his career to seek new challenges with a move to England.

Linked with moves to Arsenal and Barcelona during the summer transfer window, Piszczek is a player with recognised quality across Europe's top leagues. With Dortmund requiring £15million for his services several months ago, it would be a surprise to see them ask for anything more at this stage.

If van Gaal is in search of a player capable of contributing in the final third whilst fulfilling his basic duties in defence, then Everton's Seamus Coleman is his man. The Republic of Ireland international would be a fantastic addition at right wing-back, a position in which he is now regarded as one of the Premier League's very best.

Having seen the improvements van Gaal has made during such a short space of time at Old Trafford, Coleman could be tempted by the opportunity to join the Dutchman's revolution. Also, considering Everton’s poor league form - they sit 13th after 20 matches - now could be the time to leave Goodison Park, concluding a six-year stay with the Merseyside outfit.

Team

Key Passes

Seamus Coleman

Everton

19

Antonio Valencia

Man Utd

10

Rafael

Man Utd

6

Coleman would undoubtedly cost a fair bit, with some sources suggesting as much as £25 million, but he would provide United with a hard-working, creative wing-back - he has created 19 chances this season, more than Valencia and Rafael’s combined efforts of 16 - who is more than comfortable with operating in van Gaal's favoured 3-5-2 system.

Southampton's Nathaniel Clyne is a player likely to feature somewhere near the top of every Manchester United fan's January wish-list. A strong and pacey, yet technically gifted full-back, the 23-year-old has been one of the Saints' stand-out players this season - an achievement in itself.

He has come on leaps and bounds since his arrival from Crystal Palace 2012, enjoying an accomplished Premier League career on the south coast, despite having to adapt under three different managers in less than three years. It's fair to say he has improved with each top-flight campaign.

This season, Clyne has accrued 18 domestic appearances, scoring two goals and creating 11 chances in the process. Meanwhile, he has achieved the impressive feat of attempting more tackles than other player in the English top flight, ahead of Chelsea's Nemanja Matic.

Ironically, he turned down an approach from the Red Devils before joining the Saints some three years ago in order to further his development with regular first team football - a decision that certainly looks to have paid off. Now, United would do well to re-ignite their interest.

In truth, this is probably the least likely transfer of the trio. Nonetheless, with his current contract expiring in the summer of 2016, doubt remains over Clyne's future at St. Mary's. While Ronald Koeman claims he is unmoved by recent speculation, the pulling power of Old Trafford could soon see Southampton relinquish yet another star.

Chris Linnell

Chris is a freelance football writer from Wiltshire, England. He is currently studying Modern History and Politics at the University of Liverpool. He has written for various other sites, including the Boot Room and Bleacher Report. His work has also featured on Eurosport.